With all the hand-wringing over a Democratic "enthusiasm gap," one effort to turn out young people at the polls this November is showing real energy and promise. What's the secret? In a word, as 78-year-old John Burton, chairman of the California Democratic Party, put it, "Pot."

Proposition 19 would make it legal for Californians over 21 to possess and cultivate marijuana for personal use, and it would authorize city governments to regulate and tax commercial production and sales. Its passage would signal a major victory for common sense over a war on drugs that has been an abysmal failure in the Golden State and throughout the country. As states devastated by the fiscal crisis look for more efficient and effective alternatives to spending $50 billion a year on incarceration, a shift in California might presage changes across the nation.

It would be great if young people would take to the streets and the voting booths on issues like Afghanistan, historical levels of inequality and poverty, or to protect Social Security from a Republicans takeover. But they're not. And if it's reforming an ineffective, wasteful and racially unjust drug policy that mobilizes young people -- who are at the core of the rising American electorate along with African-Americans, Hispanics, and unmarried women -- so be it. According to Public Policy Polling, for those who cite Prop 19 as their top reason for voting, 34 percent are under age 30.

"There's nothing that motivates young people more than this issue, "Aaron Houston, executive director of Students for a Sensible Drug Policy, told me. "So much of this comes down to young people saying they don't want this war on drugs to be waged in their name anymore."

The case for Prop 19 is clear and strong. Between 1999 and 2009, nearly 570,000 residents were arrested for misdemeanor pot possession. Harvard economist Jeffrey Miron, a prominent libertarian, estimates the annual cost of enforcing prohibition in California at $1.8 billion. The new statute would save as much as $200 million per year on enforcement, prosecution and incarceration. But for all the time and resources the state has pumped into targeting these nonviolent, low-level offenders, there has been no corresponding drop in reported use. (In fact, according to surveys by the U.S. and Dutch governments, 41 percent of Americans have used marijuana, compared to 22.6 percent of residents of the Netherlands, where it is legal.)

There has, though, been a spike in racial disparities. Black adults across California are arrested for pot possession at higher rates than whites -- sometimes by a factor of 12. The same ugly imbalances apply to black youth, even though government surveys consistently show that their white peers are more likely to use pot.

Legalization would also help balance the budget. California is facing a $19 billion shortfall and can ill afford to waste so much money on a failed war on drugs. But it can surely benefit from a regulated cannabis market; advocates estimate that the state could capture $1.4 billion a year in taxes and fees.

Unions, progressives, and community activists see Prop 19 as a jobs engine and revenue generator -- especially for economically depressed communities -- which would increase resources available for health care, public safety, parks, roads, transportation and more. But it's critical to not only fight for approval of the ballot initiative but also for the infrastructure for production and distribution. Oakland's city council, for example, has already approved permits for four indoor marijuana plantations.

Because the reasons to support Prop 19 are so diverse, promising alliances are being formed that might be sustained beyond this election. Libertarians and progressives, civil rights advocates, law enforcement groups, unions and young activists all see the value of ending prohibition. (As editor of the Nation, it's not often that I find the magazine in a bipartisan alliance with Reason magazine. And the National Review was on board for legalization when William F. Buckley Jr. served as editor a decade ago.)

So Prop 19 is good policy and good politics. States across the country struggling with these same issues are watching with interest, as are Democratic strategists who see the potential for similar ballot initiatives to drive people to the polls in 2012.

Katrina vanden Heuvel is editor and publisher ofthe Nationand writes a weekly column for The Post.